PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-25 (3167)
 

Clipboard (0)
None

Select a Filter Below

Journals
Year of Publication
7.  Comparison of Robotic-assisted and Conventional Acetabular Cup Placement in THA: A Matched-pair Controlled Study 
Background
Improper acetabular component orientation in THA has been associated with increased dislocation rates, component impingement, bearing surface wear, and a greater likelihood of revision. Therefore, any reasonable steps to improve acetabular component orientation should be considered and explored.
Questions/purposes
We therefore sought to compare THA with a robotic-assisted posterior approach with manual alignment techniques through a posterior approach, using a matched-pair controlled study design, to assess whether the use of the robot made it more likely for the acetabular cup to be positioned in the safe zones described by Lewinnek et al. and Callanan et al.
Methods
Between September 2008 and September 2012, 160 THAs were performed by the senior surgeon. Sixty-two patients (38.8%) underwent THA using a conventional posterior approach, 69 (43.1%) underwent robotic-assisted THA using the posterior approach, and 29 (18.1%) underwent radiographic-guided anterior-approach THAs. From September 2008 to June 2011, all patients were offered anterior or posterior approaches regardless of BMI and anatomy. Since introduction of the robot in June 2011, all THAs were performed using the robotic technique through the posterior approach, unless a patient specifically requested otherwise. The radiographic cup positioning of the robotic-assisted THAs was compared with a matched-pair control group of conventional THAs performed by the same surgeon through the same posterior approach. The safe zone (inclination, 30°–50°; anteversion, 5°–25°) described by Lewinnek et al. and the modified safe zone (inclination, 30°–45°; anteversion, 5°–25°) of Callanan et al. were used for cup placement assessment. Matching criteria were gender, age ± 5 years, and (BMI) ± 7 units. After exclusions, a total of 50 THAs were included in each group. Strong interobserver and intraobserver correlations were found for all radiographic measurements (r > 0.82; p < 0.001).
Results
One hundred percent (50/50) of the robotic-assisted THAs were within the safe zone described by Lewinnek et al. compared with 80% (40/50) of the conventional THAs (p = 0.001). Ninety-two percent (46/50) of robotic-assisted THAs were within the modified safe zone described by Callanan et al. compared with 62% (31/50) of conventional THAs p (p = 0.001). The odds ratios for an implanted cup out of the safe zones of Lewinnek et al. and Callanan et al. were zero and 0.142, respectively (95% CI, 0.044, 0.457).
Conclusions
Use of the robot allowed for improvement in placement of the cup in both safe zones, an important parameter that plays a significant role in long-term success of THA. However, whether the radiographic improvements we observed will translate into clinical benefits for patients—such as reductions in component impingement, acetabular wear, and prosthetic dislocations, or in terms of improved longevity—remains unproven.
Level of Evidence
Level III, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.
doi:10.1007/s11999-013-3253-7
PMCID: PMC3889439  PMID: 23990446
8.  Intraarticular Fibrinogen Does Not Reduce Blood Loss in TKA: A Randomized Clinical Trial 
Background
Bleeding remains an ongoing concern after total knee arthroplasty (TKA). Intraarticular application of human fibrinogen with a topical thrombin has been described to stop diffuse bleeding in knee arthroplasty.
Questions/purposes
It was hypothesized that the use of human fibrinogen as a topical agent would result in a reduction of bleeding and transfusions required after TKA; secondary end points included comparison of early clinical results including pain scores and range of motion (ROM) at 6 weeks and complications after surgery.
Methods
Two hundred patients undergoing TKA were randomized into a double-blind clinical trial to receive either intraarticular fibrinogen 2 minutes before tourniquet release or no such treatment. Postoperative hemoglobin and hematocrit levels, drain output, and transfusion requirements were recorded and blood loss was calculated. Clinical outcomes and adverse events were tracked prospectively. Descriptive analysis was performed using a two-sample t-test.
Results
There were no differences in calculated blood loss between the fibrinogen and the control groups; the mean postoperative drain output was 780 ± 378 mL in the fibrinogen group compared with 673 ± 301 mL in the control group (p = 0.029), but the hemoglobin drop at Day 2 was 3.47 ± 1.53 g/L in the fibrinogen group and 3.84 ± 1.24 g/Ll in the control group (p = 0.051). There were no differences in in transfusions, early ROM, visual analog pain scores, or complications between the groups.
Conclusions
The use of fibrinogen in TKA did not lead to a significant reduction of blood loss or transfusions in primary TKA for osteoarthritis. Given the lack of benefits and the costs this procedure adds to TKA, its routine use cannot be justified during primary TKA for osteoarthritis.
Level of Evidence
Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
doi:10.1007/s11999-013-3036-1
PMCID: PMC3889440  PMID: 23657879
13.  Risk Factors for Early Revision After Primary TKA in Medicare Patients 
Background
Patient, surgeon, health system, and device factors are all known to influence outcomes in total knee arthroplasty (TKA). However, patient-related factors associated with an increased risk of early failure are not well understood, particularly in elderly patients.
Questions/purposes
The purpose of this study was to identify specific comorbid conditions associated with increased risk of early revision in Medicare patients undergoing TKA.
Methods
A total of 117,903 Medicare patients who underwent primary TKA between 1998 and 2010 were identified from the Medicare 5% national sample administrative database and used to determine the relative risk of revision within 12 months after primary TKA as a function of baseline medical comorbidities. Cox regression was used to evaluate the impact of 29 comorbid conditions on risk of early failure controlling for age, sex, race, census region, socioeconomic status, and all other baseline comorbidities.
Results
The most significant independent risk factors for revision TKA within 12 months were chronic pulmonary disease, depression, alcohol abuse, drug abuse, renal disease, hemiplegia or paraplegia, and obesity.
Conclusions
This information could be valuable to patients and their surgeons when making shared medical decisions regarding elective TKA and for risk-stratifying publicly reported outcomes in Medicare patients undergoing TKA.
Level of Evidence
Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.
doi:10.1007/s11999-013-3045-0
PMCID: PMC3889408  PMID: 23661301
16.  Inter- and Intraobserver Reliability of Two-dimensional CT Scan for Total Knee Arthroplasty Component Malrotation 
Background
Rotational malalignment of total knee arthroplasty (TKA) has been correlated with patellofemoral maltracking, knee instability, and stiffness. CT is the most accurate method to assess rotational alignment of prosthetic components after TKA, but inter- and intraobserver reliability of CT scans for this use has not been well documented.
Questions/purposes
The objective of this study was to determine the inter- and intraobserver reliability and the repeatability of the measurement of TKA component rotation using two-dimensional CT scans.
Methods
Fifty-two CT scans of TKAs being evaluated for revision surgery were measured by three different physicians. An orthopaedic resident and attending measured the same scans twice (more than 2 weeks apart) and a musculoskeletal radiologist measured them once. To assess interobserver reliability, intraclass correlation coefficients (ICCs) with two-way mixed-effects analysis of variance models as well as 95% confidence intervals for each were done. The repeatability coefficient was calculated as well, which is defined as the difference in measurements that include 95% of the values. This indicates the magnitude of variability among measurements in the same scale, which in this study is degrees.
Results
The interobserver ICC measurement for the femoral component was 0.386 (poor), and it was 0.670 (good) for the tibial component. The interobserver ICC for the combined rotation measurements was 0.617 (good). The intraobserver ICC for the femoral component was 0.606 (good), and it was 0.809 (very good) for the tibial component. The intraobserver ICC for combined rotation was 0.751 (good). The intraobserver repeatability coefficient for the femoral component was 0.49°, 10.64° for the tibial component, and 12.29° for combined rotation.
Conclusions
In this study, the inter- and intraobserver reliability, and the repeatability, of TKA component rotation were variable. This raises concern about whether CT scan is diagnostic in the assessment of component malrotation after TKA.
Level of Evidence
Level IV, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.
doi:10.1007/s11999-013-3111-7
PMCID: PMC3889411  PMID: 23813180
18.  Editorial Comment: Symposium: 2013 Knee Society Proceedings 
doi:10.1007/s11999-013-3368-x
PMCID: PMC3889413  PMID: 24233433
19.  Comparison of Total Knee Arthroplasty With Highly Congruent Anterior-stabilized Bearings versus a Cruciate-retaining Design 
Background
The use of a highly conforming, anterior-stabilized bearing has been associated with clinical success in a limited number of studies.
Questions/purposes
We compared Knee Society scores, radiographic results, complication rates, and revision rates with the use of anterior-stabilized bearings compared with cruciate-retaining (CR) bearings.
Methods
A series of 382 patients with 468 primary total knee arthroplasties (TKAs) between 2003 and 2008 with minimum 2-year followup were reviewed. Anterior-stabilized bearings comprised 49% (n = 228) of the sample and CR bearings consisted of 51% (n = 240). The decision to use an anterior-stabilized bearing was based on integrity of the posterior cruciate ligament (PCL) intraoperatively or after sacrifice of the PCL to achieve soft tissue balance. The tibial and femoral component designs were the same regardless of bearing choice. Outcomes were measured with Knee Society scores, complications, revision TKA, and survival. Radiographs were analyzed for component alignment and evidence of loosening.
Results
There was no difference in Knee Society knee scores, radiographic alignment, component loosening, manipulation rate, major complications, or time to revision for patients between the two groups. However, the CR group had significantly more revisions than the anterior-stabilized group (21 CR [1.5%] versus seven anterior-stabilized [4.6%], p = 0.03) at a minimum followup of 5 months (mean, 42 months; range, 5–181 months).
Conclusions
The use of a highly congruent anterior-stabilized bearing for PCL substitution has comparable clinical and radiographic results to traditional CR TKA. These results suggest that this approach is an effective method to achieve stability without the PCL in primary TKA.
Level of Evidence
Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
doi:10.1007/s11999-013-3068-6
PMCID: PMC3889414  PMID: 23690153
20.  Impact of Socioeconomic Factors on Outcome of Total Knee Arthroplasty 
Background
Few data exist regarding the impact of socioeconomic factors on results of current TKA in young patients. Predictors of TKA outcomes have focused primarily on surgical technique, implant details, and individual patient clinical factors. The relative importance of these factors compared to patient socioeconomic status is not known.
Questions/purposes
We determined whether (1) socioeconomic factors, (2) demographic factors, or (3) implant factors were associated with satisfaction and functional outcomes after TKA in young patients.
Methods
We surveyed 661 patients (average age, 54 years; range, 18–60 years; 61% female) 1 to 4 years after undergoing modern primary TKA for noninflammatory arthritis at five orthopaedic centers. Data were collected by an independent third party with expertise in collecting healthcare data for state and federal agencies. We examined specific questions regarding satisfaction, pain, and function after TKA and socioeconomic (household income, education, employment) and demographic (sex, minority status) factors. Multivariable analysis was conducted to examine the relative importance of these factors for each outcome of interest.
Results
Patients reporting incomes of less than USD 25,000 were less likely to be satisfied with TKA outcomes and more likely to have functional limitations after TKA than patients with higher incomes; no other socioeconomic factors were associated with satisfaction. Women were less likely to be satisfied and more likely to have functional limitations than men, and minority patients were more likely to have functional limitations than nonminority patients. Implants were not associated with outcomes after surgery.
Conclusions
Socioeconomic factors, in particular low income, are more strongly associated with satisfaction and functional outcomes in young patients after TKA than demographic or implant factors. Future studies should be directed to determining the causes of this association, and studies of clinical results after TKA should consider stratifying patients by socioeconomic status.
Level of Evidence
Level III, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.
doi:10.1007/s11999-013-3002-y
PMCID: PMC3889415  PMID: 23633182
22.  Does Adding Antibiotics to Cement Reduce the Need for Early Revision in Total Knee Arthroplasty? 
Background
There is considerable debate about whether antibiotic-loaded bone cement should be used for fixation of TKAs. While antibiotics offer the theoretical benefit of lowering early revision due to infection, they may weaken the cement and thus increase the likelihood of aseptic loosening, perhaps resulting in a higher revision rate.
Questions/purposes
We (1) compared the frequency of early knee revision arthroplasty in patients treated with antibiotic-loaded or non-antibiotic-loaded cement for initial fixation, (2) determined effects of age, sex, comorbidities, and surgeons’ antibiotic-loaded cement usage patterns on revision rate, and (3) compared causes of revision (aseptic or septic) between groups.
Methods
Our study sample was taken from the Canadian Joint Replacement Registry and Canada’s Hospital Morbidity Database and included cemented TKAs performed between April 1, 2003, and March 31, 2008, including 20,016 TKAs inserted with non-antibiotic-loaded cement and 16,665 inserted with antibiotic-loaded cement. Chi-square test was used to compare the frequency of early revisions between groups. Cox regression modeling was used to determine whether revision rate would change by age, sex, comorbidities, or use of antibiotic-loaded cement. Similar Cox regression modeling was used to compare cause of revision between groups.
Results
Two-year revision rates were similar between the groups treated with non-antibiotic-loaded cement and antibiotic-loaded cement (1.40% versus 1.51%, p = 0.41). When controlling for age, sex, comorbidities, diabetes, and surgeons’ antibiotic-loaded cement usage patterns, the revision risk likewise was similar between groups. Revision rates for infection were similar between groups; however, there were more revisions for aseptic loosening in the group treated with non-antibiotic-loaded cement (p = 0.02).
Conclusions
The use of antibiotic-loaded cement in TKAs performed for osteoarthritis has no clinically significant effect on reducing revision within 2 years in patients who received perioperative antibiotics. Longer followup and confirmation of these findings with other national registries are warranted.
Level of Evidence
Level III, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.
doi:10.1007/s11999-013-3186-1
PMCID: PMC3889417  PMID: 23884803
23.  Unicondylar Arthroplasty in Knees With Deficient Anterior Cruciate Ligaments 
Background
Historically, a functional ACL has been a prerequisite for patients undergoing unicondylar knee arthroplasty (UKA). However, this premise has not been rigorously tested.
Questions/purposes
We compared (1) the survivorship free from revision and (2) the failure mechanisms of UKAs in ACL-deficient knees and UKAs in ACL-intact knees performed over the same time interval.
Methods
Between November 2000 and July 2008, a fixed bearing UKA was performed in 72 patients (81 knees) with intraoperatively confirmed ACL deficiency. Five patients (five knees) with preoperative instability underwent ACL reconstruction and were excluded from analysis. Of the remaining 67 patients (76 knees) without preoperative instability, implant status was known for 68 UKAs in 60 patients. Survivorship and failure mechanisms for these knees were compared to those of 706 UKAs in ACL-intact knees performed during the same time interval by the same surgeon using the same implant system. Minimum followup for the ACL-deficient group was 2.9 years (mean, 6 years; range, 2.9–10 years).
Results
Revision rates between UKAs with and without intact ACLs were similar in the absence of clinical instability (p = 0.58). Six-year UKA survivorship was 94% (95% CI: 88%–100%) in ACL-deficient knees and 93% (95% CI: 91%–96%) in ACL-intact knees (p = 0.89). Five knees (7%) in the ACL-deficient group were revised: disease progression (two), loose tibia (one), persistent pain (one), and revised elsewhere/reason unknown (one). Thirty-six knees in the ACL-intact group underwent revision (5%): aseptic loosening (13), revised elsewhere/reason unknown (11), disease progression (three), tibial subsidence/fracture (four), infection (three), pain (one), and lateral compartment overload (one).
Conclusions
At 6 years, deficiency of the ACL in patients without clinical knee instability did not impact the survivorship of UKAs compared to UKAs performed in knees with intact ACLs.
Level of Evidence
Level III, prognostic study. See Instructions for Authors for a complete description of levels of evidence.
doi:10.1007/s11999-013-2982-y
PMCID: PMC3889418  PMID: 23572351
25.  Preliminary Results Suggest Tranexamic Acid is Safe and Effective in Arthroplasty Patients with Severe Comorbidities 
Background
Tranexamic acid (TXA) reduces blood loss and transfusion after total joint arthroplasty (TJA) but concerns remain that patients with severe medical comorbidities might be at increased risk for thromboembolic complications.
Questions/purposes
Among patients undergoing primary TJA with severe systemic medical disease, (1) was TXA associated with increased symptomatic thromboembolic events; (2) was TXA associated with decreased blood transfusion rates; and (3) were there differences in symptomatic thromboembolism or transfusions in the subset of patients with a history of, or risk factors for; thromboembolic disease?
Methods
We performed a retrospective review of 1131 primary TJAs in 1002 patients with American Society of Anesthesiologists score III or IV. Of these, 402 had at least one of seven risk factors for thromboembolic events and were designated as high risk; 240 of those patients received TXA. Outcome measures included 30-day postoperative symptomatic thromboembolic events and postoperative transfusion.
Results
There were no differences in symptomatic thromboembolic events within 30 days of surgery between patients who received TXA and those who did not (2.5% versus 2.6%, p = 0.97). Fewer patients treated with TXA received transfusions (11% with versus 41% without; p < 0.0001). In high-risk patients, TXA was not associated with an increase in symptomatic thromboembolic events (6.7% with versus 4.3% without; p = 0.27) and was associated with a decrease in transfusion rates (17% with versus 48% without; p = 0.001).
Conclusions
Although TXA seemed safe and effective in this database review of patients with severe medical comorbidities, a larger prospective trial is warranted to confirm these results.
Level of Evidence
Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
doi:10.1007/s11999-013-3134-0
PMCID: PMC3889421  PMID: 23817754

Results 1-25 (3167)